The assembler language supported by High Level Assembler has functional extensions to the languages supported by Assembler H Version 2 and DOS/VSE Assembler. High Level Assembler uses the same language syntax, function, operation, and structure as Assembler H Version 2. Similarly, the functions provided by the Assembler H Version 2 macro facility are all provided by High Level Assembler.

Except for these possible conflicts, and with the appropriate High Level Assembler option values, source language source programs written for Assembler H Version 2 or DOS/VSE Assembler, that assemble without warning or error diagnostic messages, should assemble correctly using High Level Assembler.

z/VSE

An E-Deck refers to a macro source book of type E that can be used as the name of a macro definition to process in a macro instruction. E-Decks are stored in edited format, and High Level Assembler requires that library macros be stored in source statement format. A library input exit can be used to analyze a macro definition, and, in the case of an E-Deck, call the z/VSE ESERV program to change, the E-Deck definition, line by line, back into source format required by the assembler, without modifying the original library file.

See the section titled Using the High Level Assembler Library Exit for Processing E-Decks in the z/VSE: Guide to System Functions. This section describes how to set up the exit and how to use it.